This invention relates to electrical power supplies in general and in particular to an AC power supply augmented by an internal DC battery source.
Power supplies having an internal DC battery are well known as disclosed for example in U.S. Pat. No. 3,319,074 to Koch, wherein an external AC source is rectified and applied to a load under control of a transistor. The DC battery compensates for any fluctuations of the AC source and is maintained in a fully charged condition according to the Koch patent. Operation of such power supplies while designed to maintain a constant voltage on the load, introduces additional power losses and does not cope with the varying demands of AC loads insofar as the efficient supply of energy is concerned.
It is therefore an important object of the present invention to provide an AC power supply of the type having an internal DC battery, which operates to reduce the power drawn from the external AC source to which the power supply in connected.